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Discussion Starter #1
Hello all,

I am about to purchase a 1979 CX500 custom as my first bike. Bike is running fine, the only issue my friends dad (very mechanically knowledgeable) was able to spot was a coolant leak when we started the bike. the leak can be seen on on the right side of the bike where the water pipe is connected to the engine. There is an O-ring right there and we think that if we replace the O-ring the leak will stop. I am hoping this can be done without taking the whole engine out (which some people online have already told me). Below are pictures from the manual and the bike showing exactly what I am talking about.

IMG_3157.JPG
I want to remove the water pipe (43) and replace O-ring (44)

IMG_3158.JPG IMG_3159.JPG
More pictures from manual highlighting the water pipe (red) and the location of the O-ring (green)

left side.jpg
This is a random pic online of the bike where I think I highlighted the same water pipe and circled the exact spot where I saw the leak (99% this was the spot)

I want to do this job without removing the engine. I am hoping I can just disconnect the water pipe from the radiator and engine and just put it back with a new O-ring in place. So my questions are:

Is this leak detrimental to the bikes function to ride safely?

Do you think replacing the O-ring will stop the leak?

Can I perform the job without removing the engine?
 

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First, when we refer to left or right, it is always as if you were sitting on the seat, ready to ride. That pipe is on the left side. Yes, that Oring can be replaced without removing the engine. As I said in your other post, however, that may not be the culprit, as the mechanical seal is quite close to that area. So make sure you identify exactly where the leak is before you dig in.

Joel in the Couve
 

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Discussion Starter #4
If it is just the Oring I can fix it. But if the water seal is the problem there is no way I can do that. I am sorry for being a newbie and posting three times about this issue. I am just nervous and thank you very much for the quick responses (and left/right knowledge of the bike). However, will the leak a problem that will be an affect the bike's ability to ride safely?
 

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If it is just the Oring I can fix it. But if the water seal is the problem there is no way I can do that. I am sorry for being a newbie and posting three times about this issue. I am just nervous and thank you very much for the quick responses (and left/right knowledge of the bike). However, will the leak a problem that will be an affect the bike's ability to ride safely?

There are many threads on the mechanical seal issue. If it is just dripping a bit, you should probably ignore it for a while as it may seal itself. If not, look up the Shep method of replacement. It requires only modest skills and tools, but you do have to have (or buy) at least a small torch.

I recently did it. I am definitely not a motorcycle mechanic, so it took me a while, but it is not rocket science either.

BTW, just use Google to search this forum.
 

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Discussion Starter #6
Thanks so much. I am doing the best research I can. I going to google that Shep method now.
 

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Discussion Starter #7
I talked to my friend's dad who spotted the leak. We wiped down that section of the bike, turned it back on, and he noticed that the leak was definitely coming from where the water pipe is attached to the engine. He saw it bubble and spit out the coolant. If this is the case, this would not be an issue where we would have to replace the seal inside? I think not right it has to be the Oring.

Again, thanks in advance.
 

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If you try to replace the o-ring, no need to remove the radiator end of the water pipe. Leave that end attached, remove the clamps and pull the water pipe out of the water pump housing; all with the engine still in the bike. If it turns out that you need to replace the mechanical seal, research the Shep method; all with the engine still in the bike. Good luck, enjoy the bike.
Run with the leak for a while if you want, just keep an eye on the coolant level in the radiator and make sure that the temperature gauge is functioning.
 

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Discussion Starter #10
Thank you again to everyone helping me out. I have been nervous all day. I am very glad for the helpful community here and to be a part of once become the owner of this bike.
 

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Speaking of checking the coolant level.....always do this at the radiator cap, don't rely on the reserve bottle for this, or for adding new coolant. The system doesn't work that way. Once the radiator is at the right level, THEN check the reserve bottle, and top off if needed. The manual has all this, as does the WIKI.

Joel in the Couve
 
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